The main clinical features of MAN1B1 deficiency are mental retardation, motor-developmental delay, dysmorphic findings (prominent eyebrows with lateral thinning, downward-sloping palpebral fissures, a bulbous nose tip, large ears, and a thin upper lip), truncal obesity, and hypotonia. Truncal obesity is unique to this CDG. Other clinical findings in MAN1B1 patients reported in the literature are as follows:
• Macrocephaly
• Hipsarrythmia and West syndrome
• Abnormal EEG findings
• Speech delay
• Horizontal nystagmus
• Myopathy
• Demyelinating neuropathy
• Retinal coloboma
• Long slender fingers
• Joint hypermobility
• Skin laxity
• Scoliosis
• MCA infarct due to low protein C and S activity
• Aortic aneurysm
• Hyperphagia
• Hypersialorrhea
• Hypertransaminasemia
MRI findings include high signal diffuse areas on T2-FLAIR weighted imaging in the subcortical regions, mainly in the posterior areas, against the background of incomplete myelination and cerebellar hypoplasia and atrophy. Normal MRI findings have also been reported.
MAN1B1